The present invention relates to a method for diagnosing cancer. More specifically, the method permits accurate diagnosis of cancer in vitro through quantitative measurement of radicals found in cells. An ESR spectrometer is used for this purpose, with said cells from a patient mixed with a solution of hematoporphyrin or hematoporphyrin derivative.
In an area of cancer diagnosis, another method that has recently gained in popularity is the one in which a light-sensitive material, such as hematoporphyrin, and a laser beam are used. This method can be summarized as follows:
(a) intravenous injection of a light-sensitive material which has an affinity for tumors;
(b) accumulation of the material in the tumor for three days or more;
(c) application of a laser beam to the tumor through an optical fiber; and
(d) observation of fluorescence radiated from the tumor as a result of laser beam irradiation.
Since this method relates to diagnosis in vivo and requires considerable time for accumulation, it is unavoidable that a patient will experience both physical and mental discomfort.